A urisheath is a product used in urinary catheter devices for aiding in male urinary incontinence and similar uses. The urisheath comprises a cylindrical sleeve enclosing the shaft of the penis and a tip portion to which a hose may be connected ending in a urine collection bag.
A urisheath is traditionally made by dipping a mandrel with a corresponding design into a latex solution. The dipping process may be repeated several times and the latex is cured between the immersions.
WO 91/17728 discloses a method for manufacturing a urisheath by thermoplastic processing of a thermoplastic material. The tip portion is produced by injection molding in a tool whereas the thin-walled cylindrical portion is produced integrally with the tip portion by a controlled extrusion and blow-molding.
WO 2004/004796 discloses a method for producing a urisheath in a thermoplastic process for providing a urisheath, which is substantially clear to allow inspection of an area of the skin beneath the urisheath with the urisheath material in contact with the skin. The tip portion may be produced by injection molding and the cylindrical portion by extrusion, extrusion blow molding, injection blow molding or cold rolling. The tip portion may form an integral part with the cylindrical portion or may be produced as a separate unit, which is subsequently connected with the cylindrical portion. It is also possible to produce the urisheath entirely by extrusion blow-molding.
It is noted that urisheaths made of latex are no longer permitted or suitable in many countries because of interactions with the skin. A urisheath made of a thermoplastic material is feasible. However, the thermoplastic material requires addition of plasticizers, which may involve problems in certain cases. A plasticizer can cause migration problems, which eventually can cause biological safety issues, and which also can cause deterioration of the performance of the skin adhesive on the urisheaths. A plasticizer can in certain cases also cause environmental problems. Urisheaths made of silicone plastic materials are known in the art. However, such silicone urisheaths are normally made by dipping a mandrel in a suitable silicone solution, one time or several times as mentioned above in connection with latex urisheaths. This process is time-consuming. Moreover, it is difficult to control the wall thickness in such a production method.
Injection molding of silicone materials is previously known from e.g. EP 162 037. This patent discloses a method of producing a silicone matt or silicone domes by injection molding of a silicone material into a cavity having a corresponding shape. The material may be a two-component silicone material being injected at a low temperature. The cavity and the form portions may be heated to a high temperature for rapid curing of the silicone material.
In such an injection-molding machine it may be difficult to remove the air when the cavity is filled with material. This problem is addressed in EP 979 718, which discloses suction ports for removing the air.